The inventive subject matter relates generally to the field of experimentation and more particularly, to experimentation and optimization of the delivery of content to users within a digital network, such as the Internet. By the testing of marketing tactics, propositions, advertisements and offers businesses can optimize their campaigns and customer management procedures. For instance, an on-line retailer might test the effectiveness of different headlines and benefit statements in on-line advertising. An advertiser might test placing different advertisements across different advertising placements offered by different publishers. A bank might test different contact and offer strategies in direct mail and outbound telemarketing to cross-sell financial services based on changes to a customer's account balances. A telecommunications company might test different offers and bundles of services to existing customers over the Internet and to their customer's mobile phones. Increasingly, businesses are advertising across a variety of mediums including search engines, banner advertising, contextual advertising, interactive TV, while completing transactions from their own web site. While the flow across these channels for a prospect may be seamless and driven optimal campaign elements across these different systems is challenging for businesses.